Composite Particles, Method of Refining and Use Thereof

ABSTRACT

Composite particles with lower mean particle size and smaller size distribution are obtained through refining treatments. The refined composite particles, such as ceria coated silica particles are used in Chemical Mechanical Planarization (CMP) compositions to offer higher removal rate; very low within wafer (WWNU) for removal rate, low dishing and low defects for polishing oxide films.

CROSS-REFERENCE OF RELATED APPLICATIONS

This application claims the benefit of priority to U.S. provisionalapplication Ser. No. 62/316,089, filed Mar. 31, 2016, which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

Chemical mechanical planarization (“CMP”) polishing compositions (CMPslurries, CMP composition or CMP formulations are used interchangeably)are used in the production of a semiconductor device. The presentinvention relates to polishing compositions comprising refined compositeparticles (used as abrasive particles) that are especially suitable forpolishing patterned semiconductor wafers that comprise silicon oxidematerials.

Silicon oxide is widely used as dielectric materials in semiconductorindustry. There are several CMP steps in integrated circuit (IC)manufacturing process, such as shallow trench isolation (STI),inter-layer dielectric (ILD) CMP and gate poly CMP etc. Typical oxideCMP slurry involves: abrasive, with or without other chemicals. Otherchemicals could be dispersants to improve slurry stability, boosters toincrease removal rate, or inhibitors to decrease removal rate and tostop on the other film, for example, SiN for STI application.

Desirable characteristics for a CMP slurry at advanced semiconductortechnology nodes are reduced defects, high removal rates, very low withwafer non uniformity (WWNU) for removal rates and low topography. Havinga very low WWNU for removal rates is particularly important. A highernon-uniformity would lead to over-polish in the regions on the waferswhere removal rates and under-polish where least material is removed.This would create uneven topography on the wafer surface which isundesirable in semiconductor manufacturing. Therefore, considerable CMPprocess development is required in terms of pads, conditioning,polishing zone pressure adjustments to yield desired uniform removalrate profile.

Among common abrasives used in CMP slurries, such as silica, alumina,zirconia, titania and so on, ceria is well-known for its high reactivitytoward silica oxide and is widely used in STI CMP slurry for the highestoxide removal rate (RR) due to the high reactivity of ceria to silica.

Cook et al. (Lee M. Cook, Journal of Non-Crystalline Solids 120 (1990)152-171) proposed a ‘chemical tooth’ mechanism to explain thisextraordinary property of ceria. According to this mechanism, when ceriaparticles are pressed onto silicon oxide film, ceria breaks down silicabonds, forms a Ce—O—Si structure and thus cleavage silica from thesurface.

Most of the ceria used in CMP industry are manufactured fromcalcinations-wet milling process. The resulted ceria has sharp edges andvery wide size distribution. It also has very large “large particlecount” (LPC). All of these are believed to be responsible for defectsand low yields, especially scratch after the wafer is polished.Different forms of ceria containing particles such as colloidal ceria orceria coated silica particles are also being considered to resolve thesechallenging issues.

Ceria coated silica particles have been found especially useful forachieving high removal rates of silicon oxide films with lowerdefectivity (PCT/US16/12993). Yet the need exists still to furtherimprove the removal rates, control the removal ratewithin-wafer-non-uniformity (WWNU) and reduce polishing defects.

The present invention relates to refined agglomerated compositeparticles, methods of refinement and method of using the refinedcomposite particles in polishing applications that can achieve theperformance requirements.

Therefore, there are significant needs for CMP compositions, methods,and systems that can offer excellent within wafer non-uniformity forremoval rates and higher removal rates and low defects.

BRIEF SUMMARY OF THE INVENTION

Described herein are refined composite particles, method of refining anduse thereof.

In one aspect, the present invention is composite particles comprisesingle ceria coated silica particles and aggregated ceria coated silicaparticles; wherein more than 99 wt % of the composite particlescomprising the number of single ceria coated silica particles rangingfrom 10 or less (≦10) to 2 or less (≦2), such as≦10, ≦5, ≦4, ≦3, and ≦2.

In another aspect, the present invention is a process of refiningcomposite particles comprising single and aggregated particles to reducelarge aggregates, comprising at least one step selected from the groupconsisting of (1) filtration; (2) bowl centrifuge; (3) fixed anglerotational centrifuge; (4) gravitational settling; (5) calcination andmilling process modifications; and combinations thereof; wherein thesingle particles comprising core particles with surfaces covered bynanoparticles; wherein the core particle is selected from the groupconsisting of silica, alumina, titania, zirconia, polymer particle, andcombinations thereof; and the nanoparticle is selected from thecompounds of a group consisting of zirconium, titanium, iron, manganese,zinc, cerium, yttrium, calcium, magnesium, fluorine, lanthanum,strontium nanoparticle, and combinations thereof.

In yet another aspect, the present invention is a chemical mechanicalplanarization (CMP) polishing composition, comprising

-   -   composite particles comprise single ceria coated silica        particles and aggregated ceria coated silica particles; wherein        more than 99 wt % of the composite particles comprising of 5,        preferably 4, or more preferably 2 single ceria coated silica        particles;    -   water;    -   pH of the CMP composition ranges from about 2 to about 12,        preferably about 3.5 to about 10, more preferably from about 4        to about 7;    -   and    -   optionally    -   a pH adjusting agent;    -   a surfactant; and    -   biological growth inhibitor.

In yet another aspect, the present invention is a polishing method forchemical mechanical planarization (CMP) of a semiconductor substratecomprising at least one surface having at least one oxide layer,comprising the steps of:

-   -   a) contacting the at least one oxide layer with a polishing pad;    -   b) delivering a CMP polishing composition to the at least one        surface, and    -   c) polishing the at least one oxide layer with the CMP polishing        composition;    -   wherein the CMP polishing composition comprises    -   composite particles comprise single ceria coated silica        particles and aggregated ceria coated silica particles; wherein        more than 99 wt % of the composite particles comprising of 5,        preferably 4, or more preferably 2 single ceria coated silica        particles;    -   water;    -   pH of the CMP composition ranges from about 2 to about 12,        preferably about 3.5 to about 10, more preferably from about 4        to about 7;    -   and    -   optionally    -   a pH adjusting agent;    -   a surfactant; and    -   biological growth inhibitor.

In yet another aspect, the present invention is a system for chemicalmechanical planarization, comprising:

-   -   a semiconductor substrate comprising at least one surface having        at least one oxide layer;    -   a polishing pad; and    -   a CMP polishing composition;    -   wherein    -   the at least one oxide layer is in contact with the polishing        pad and the polishing composition; and    -   the CMP polishing composition comprises        -   composite particles comprise single ceria coated silica            particles and aggregated ceria coated silica particles;            wherein more than 99 wt % of the composite particles            comprising of 5, preferably 4, more preferably 2 single            ceria coated silica particles;        -   water;        -   pH of the CMP composition ranges from about 2 to about 12,            preferably about 3.5 to about 10, more preferably from about            4 to about 7;        -   and        -   optionally        -   a pH adjusting agent;        -   a surfactant; and        -   biological growth inhibitor.

The pH adjusting agent includes but is not limited to sodium hydroxide,cesium hydroxide, potassium hydroxide, cesium hydroxide, ammoniumhydroxide, quaternary organic ammonium hydroxide, and combinationsthereof;

The chemical additive includes but is not limited to a compound having afunctional group selected from the group consisting of organiccarboxylic acids, amino acids, amidocarboxylic acids, N-acylamino acids,and their salts thereof; organic sulfonic acids and salts thereof;organic phosphonic acids and salts thereof; polymeric carboxylic acidsand salts thereof; polymeric sulfonic acids and salts thereof; polymericphosphonic acids and salts thereof; arylamines, aminoalcohols, aliphaticamines, heterocyclic amines, hydroxamic acids, substituted phenols,sulfonamides, thiols, polyols having hydroxyl groups, and combinationsthereof;

The composite particles can comprise single ceria coated silicaparticles and aggregated ceria coated silica particles; wherein 99 wt %of the composite particles have particle size less than 250 nm,preferably less than 200 nm, and more preferably less than 190 nm.

The ceria coated silica particles can further have mean particle sizeless than 150 nm, preferably less than 125 nm, or more preferably lessthan 110 nm; wherein the mean particle size is the weighted average ofparticle diameters.

The ceria coated silica particles are amorphous silica ceria particleshaving surfaces covered by singly crystalline ceria nanoparticles.

The change of size distribution of composite particles under adisintegrative force is less than 10%, preferably less than 5%, or morepreferably less than 2%.

When the semiconductor substrate further comprising a nitride layer, theCMP polishing provides a removal selectivity of the at least one oxidelayer over the nitride layer is more than 10. The removal selectivity ofTEOS over silicon nitride layer is more than 20.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows the particle size distribution of clusters of single ceriacoated silica particles by Disc Centrifuge Particle Size Analyzer.

FIG. 2 shows Comparison of particle size distributions with variousparticle size refinement treatments.

FIG. 3 shows Comparison of particle size distributions from three groupsA, B and C of ceria coated silica particles.

DETAILED DESCRIPTION OF THE INVENTION Composition Particles

Composite particles contain primary (or single) particles and aggregatedprimary (or single) particles. A primary particle has a core particleand many nanoparticles covering the surface of the core particle.

The core particle is selected from the group consisting of silica,alumina, titania, zirconia, and polymer particle. The nanoparticles areselected from the group consisting of oxides of zirconium, titanium,iron, manganese, zinc, cerium, yttrium, calcium, magnesium, fluorine,lanthanum and strontium nanoparticles. One of the examples of thecomposite particles is to have silica as the core particles and ceria asthe nanoparticles; and each silica core particle has ceria nanoparticlescovering its shell. The surface of each silica particle is covered byceria nanoparticles. The silica base particles are amorphous; and theceria nanoparticles are singly crystalline.

The primary particle can have an amorphous oxide layer including atleast one type of element among aluminum, zirconium, titanium, iron,manganese, zinc, cerium, yttrium, calcium, magnesium, fluorine,lanthanum silicon, and strontium on the surface of an amorphous silicaparticle A, and a crystalline oxide layer B including at least one typeof element selected from among zirconium, titanium, iron, manganese,zinc, cerium, yttrium, calcium, magnesium, fluorine, lanthanum andstrontium thereupon. The nanoparticles covering the silica coreparticles may also have a thin layer of silicon containing filmscovering the surface either partially or fully.

Ceria coated silica particles can be made using any suitable methods.For example, methods to make such particles are described inPCT/JP2016/060535, JP20131191131, JP2013133255, JP2015-169967, and JP2015-183942.

Typically, the method of forming composite particles, such as, ceriacoated silica particles involves deposition of cerium compounds onsilica core particles, followed by a calcination step and a millingstep. However, the calcination step results in agglomeration ofparticles. Some of the examples ways to reduce the number of aggregatedparticles would be to use lower calcination conditions such as lowertemperature or calcination time, more aggressive milling conditions, useof dispersants during milling, use of post-milling processing such ascentrifugation or filtering or any other technique that reduces thenumber of aggregated particles

The amount of nanoparticles covering the surface of the core particlespreferably falls within the following range in terms of the solid weightratio. The solid weight (b) of the nanoparticles relative to the solidweight (a) of the core particles is (b)/(a)=0.01 to 2, preferably 0.25to 1.5, or most preferably between 0.5 and 1.3.

Diameter of the ceria nanoparticles covering the core particle is morethan 1 nm, or preferably greater than 10 nm, preferably more than 13 nm.Having larger ceria particle diameter would allow higher removal rate tobe possible.

Diameter of the core particles may range from 10 nm to 500 nm,preferably between 20 nm to 200 nm, most preferably between 50 nm and150 nm. The core particles are larger than the nanoparticles.

Typically, the method of forming ceria coated silica particles involvesdeposition of cerium compounds on silica core particles, followed by acalcination step and a milling step. However, the calcination stepresults in agglomeration of particles. These agglomerated particles aremade of clusters of primary particles.

Each of the primary (or single) particles is spherical and uniform insize and may have a diameter between 50 and 300 nm.

The primary (or single) particles can be physically bonded into cohesiveorganized clusters to form agglomerated particles. The clusters contain2 to 50 primary (or single) particles.

The agglomerated particles have a continuous distribution in size fromindividual primary particles up to clusters containing 50 primaryparticles.

The mean particle size is the weighted average of particle diameters.For example,

Weight average mean particle size=(W1*D1+W2*D2+ . . . Wn*Dn)/(W1+W2+ . .. Wn);

where W1, W2 . . . Wn: weight fractions of particles in particle sizebins defined by particle diameters D1, D2, . . . Dn.

The size distribution of agglomerated particles is distinguished in aweight % versus particle diameter profile such that individual peaks orlocal maximum are determined by the hydraulic diameter of the clusters.

The size distribution of agglomerated particles can be determined byusing suitable particle size measurement techniques such as disccentrifuge (DC), dynamic light scattering (DLS), Single Particle OpticalSizing (SPOS), electron microscopy. Preferred method forcharacterization of particle size distribution are techniques based onDisc Centrifuge (DC).

FIG. 1 shows a typical size distribution of agglomerated ceria coatedsilica particles by Disc Centrifuge Particle Size Analyzer. Thecharacteristic peaks for the particle clusters are also shown in FIG. 1.

The peaks followed a pattern where the hydraulic diameter of eachsubsequent cluster, made up of n primary particles, is given by:

Diameter of the cluster=Diameter of the primary particle×na

where n=number of primary particles in the cluster and ¼<a<⅓.

The reduction in the number of aggregated particles can be achieved byusing any one and any combinations of (1) Filtration; (2) BowlCentrifuge; (3) Fixed angle rotational Centrifuge; (4) Gravitationalsettling; and (5) Optimization of calcination and milling processes.

The reduction in the number of aggregated particles can also bedetermined by using suitable particle size measurement techniques suchas disc centrifuge (DC), dynamic light scattering (DLS), Single ParticleOptical Sizing (SPOS), electron microscopy. Preferred method forcharacterization of particle size distribution are techniques based onDisc Centrifuge (DC).

Another aspect of the refined ceria coated silica particles is that theydo not disintegrate under disintegrative forces. Particle stabilityunder disintegrative forces can be determined by subjecting theformulation to the ultrasonication treatment for half an hour andmeasuring the changes in size distribution. Preferred conditions forultrasonication treatment are ½ hour immersion in bath with 42 KHZfrequency at 100 W output. Particle size distribution can be measured byusing any suitable technique such as Disc Centrifuge (DC) method orDynamic Light Scattering (DLS).

Changes in size distribution after the ultrasonication treatment can becharacterized in terms of changes in mean particle size, or D50 (50 wt %particles below this size and 50 wt % larger than this size), or D99 (99wt % particles below this size and 1 wt % larger than this size) or anysimilar parameters.

Preferably the changes in particle size distribution of ceria coatedsilica particles after ultrasonication treatment is less than 10%,preferably less than 5%, or more preferably less than 2%; by using forexample DC and mean particle size, D50, D75 and/or D99.

Chemical Mechanical Planarization (CMP)

The refined aggregated particles can be used as abrasive particles inCMP compositions (or CMP slurries, or CMP formulations).

An example is STI (Shallow Trench Isolation) CMP formulations, to polishoxide films, such as various metal oxide films; and various nitridefilms. In STI formulations, the formulations comprising silica coatedceria composite particles can provide very high removal rates of siliconoxide films and very low removal rates of silicon nitride polish stopfilms. These slurry formulations can be used to polish a variety offilms and materials including but not limited to thermal oxide, TetraEthyl Ortho Silicate (TEOS), High Density Plasma (HDP) oxide, HighAspect Ratio Process (HARP) films, fluorinated oxide films, doped oxidefilms, organosilicate glass (OSG) low-K dielectric films, Spin-On Glass(SOG), polymer films, flowable Chemical Vapor Deposited (CVD) films,optical glass, display glass.

The formulations can also be used in stop-in-film applications, wherethe polishing is stopped once the topography is removed and a flatsurface is achieved. Alternatively, these formulations can be used inapplications that involve polishing the bulk film and stopping at astopper layer. These formulations can be used in a variety ofapplications including but not limited to Shallow Trench Isolation(STI), Inter Layer Dielectric (ILD) polish, Inter Metal Dielectric (IMD)polish, through silicon via (TSV) polish, poly-Si or amorphous-Si filmpolishing, SiGe films, Ge films and III-V semiconductor films.

The formulations may also be used in any other applications such asglass polishing or solar wafer processing or wafer grinding where highremoval rates are desired.

In certain embodiments, polishing formulations can be used to polishsilicon oxide films at polish rates greater than 2000 Angstroms/minwhile having polish rates of silicon nitride and poly-Si films less than160 Angstroms/min.

In some other embodiments, removal rate selectivity between siliconoxide films and poly-Si films may be between 1:4 and 4:1.

By reducing the number of clusters which have large number of primaryparticles in the CMP slurries, significant and unexpected improvementcan be seen in terms of high removal rates, very low within wafer (WWNU)for removal rate, a flat removal rate profile, low dishing and lowdefects.

In one embodiment, CMP polishing composition comprise ceria coatedsilica particles with D99 is less than 250 nm or preferably less than200 nm, where D99 is defined as the particle size threshold at which 99%of the total particles by weight have particle size smaller than D99 and1% of the total particles have particle size larger than D99 based onparticle size distribution as measured by Disk Centrifuge (DC) particlesize analysis.

In another embodiment, CMP polishing composition comprise ceria coatedsilica particles with mean particle size as measured by Disc Centrifugeparticle size analysis is less than 150 nm or preferably less than 125nm or more preferably less than 110 nm.

In another embodiment CMP polishing composition comprise ceria coatedsilica particles with mean particle size as measured by Disc Centrifugeparticle size analysis is less than 150 nm or preferably less than 125nm or more preferably less than 110 nm and D99 is less than 250 nm orpreferably less than 200 nm.

In another embodiment CMP polishing composition comprise ceria coatedsilica particles with mean particle size as measured by Disc Centrifugeparticle size analysis is less than 150 nm or preferably less than 125nm or more preferably less than 110 nm and D99 is less than 250 nm orpreferably less than 200 nm and show a change of size distribution ofparticles under a disintegrative force of less than 10%.

In another embodiment the CMP polishing composition comprise ceriacoated silica particles which have less than 1% by weight of the totalparticles are aggregates comprising of 5 or more primary ceria coatedsilica particles. A primary ceria coated silica particle is a single,non-aggregated ceria coated silica particle.

In certain embodiments, CMP formulations comprise ceria coated silicaparticles with particle refinement such that the number of aggregateclusters comprising at least 5 particles constitute less than 1 wt % ofthe total weight of particles as measured by Disc Centrifuge (DC) orpreferably the number of aggregate clusters comprising at least 4particles constitute less than 1 wt % of the total weight of particlesas measured by Disc Centrifuge (DC) or even more preferably the numberof aggregate clusters comprising at least 3 particles constitute lessthan 1 wt % of the total weight of particles as measured by DiscCentrifuge (DC). In most preferred refinement, entire particledistribution would comprise mostly of non-aggregated primary compositeparticles with number of aggregate clusters comprising at least 2particles constitute less than 1 wt % of the total weight of particlesas measured by Disc Centrifuge (DC).

In some embodiments, CMP formulations comprise ceria coated silicaparticles with particle refinement such that the number of aggregateclusters comprising 2 or less (≦2), primary particles constitute morethan 85 wt % of the total weight of particles as measured by DiscCentrifuge (DC) or more preferably the number of aggregate clusterscomprising 2 or less primary particles constitute more than 90 wt % ofthe total weight of particles as measured by Disc Centrifuge (DC) oreven more preferably the number of aggregate clusters comprising 2 orless primary particles constitute more than 95 wt % of the total weightof particles as measured by Disc Centrifuge (DC). In most preferredrefinement, entire particle distribution would comprise mostly ofnon-aggregated primary composite particles with number of aggregateclusters comprising 2 or less primary particles constitute more than 99wt % of the total weight of particles as measured by Disc Centrifuge(DC).

In some embodiments, the ratio of D99 to the core particle size (asmeasured by measuring average diameter of core particles by transmissionelectron microscopy) is more preferably less than 3 or most preferablyless than 2.

In another embodiment CMP slurry formulation comprise ceria coatedsilica particles which have been refined such that the mean particlesize as measured by Disc Centrifuge particle size analysis after therefinement is reduced by at least 25 nm or more preferably more than 35nm relative to the unrefined particles.

In another embodiment, a particle size distribution refinement method isused to reduce the number of large aggregates in ceria coated silicaparticles used in CMP formulations. Methods of particle sizedistribution refinement could include centrifugation, gravitationalsettling, and optimization of calcination and milling of ceria coatedsilica particles.

In another embodiment, described herein is a system for chemicalmechanical planarization, comprising: a semiconductor substratecomprising at least one surface having at least one oxide layer;polishing pad; and a polishing composition comprising: ceria coatedsilica particles D99 is less than 250 nm or preferably less than 200 nm.

In another embodiment, described herein is a system for chemicalmechanical planarization, comprising: a semiconductor substratecomprising at least one surface having at least one oxide layer;polishing pad; and a polishing composition comprising: ceria coatedsilica particles D99 is less than 250 nm or preferably less than 200 nmand show a change of size distribution of particles under adisintegrative force of less than 10%.

In another embodiment, described herein is a system for chemicalmechanical planarization, comprising: a semiconductor substratecomprising at least one surface having at least one silicon oxide layer;polishing pad; and a polishing composition comprising: ceria coatedsilica particles which have less than 1% by weight of the totalparticles are aggregates comprising of 4 or more or 5 or more primaryparticles (single, non-aggregated ceria coated silica particles).

In another embodiment, described herein is a system for chemicalmechanical planarization, comprising: a semiconductor substratecomprising at least one surface having at least one oxide layer;polishing pad; and a polishing composition comprising: ceria coatedsilica particles with Mean Particle Size as measured by Disc Centrifugeparticle size analysis is less than 150 nm or preferably less than 125nm or more preferably less than 110 nm.

In another embodiment, described herein is a system for chemicalmechanical planarization, comprising: a semiconductor substratecomprising at least one surface having at least one silicon oxide layer;polishing pad; and a polishing composition comprising: ceria coatedsilica particles with Mean Particle Size as measured by Disc Centrifugeparticle size analysis is less than 150 nm or preferably less than 125nm or more preferably less than 110 nm; and D99 is less than 250 nm orpreferably less than 200 nm.

Another aspect of use of ceria coated silica particles that do notdisintegrate under polishing forces. It is hypothesized that if theparticles do not breakdown under the action of polishing forces (i.e.disintegrative forces) and keep the characteristic of original particlesize, then the removal rate would remain high. If the particles on theother hand disintegrate under polishing forces, the removal rate woulddecrease as the ceria nano-particles on the surface responsible for highremoval rates may come loose. Breaking of the particles may also yieldirregular shaped particles which potentially have undesirable effect onscratching defects.

Using such stable particles in CMP slurry formulations would allow moreeffective utilization of polishing forces for film material removal andwould also prevent generation of any irregular shapes that wouldcontribute to scratching defects

Since advanced CMP applications require extremely low levels of metalssuch as sodium on the dielectric surface after polishing, it is desiredto have very low trace metals, especially sodium in the slurryformulations. In certain preferred embodiments the formulations compriseceria coated silica particles that have less than 5 ppm, more preferablyless than 1 ppm most preferably less than 0.5 ppm of sodium impuritylevels for each percent of particles in the formulations by weight.

The CMP composition comprises refined composite particles as abrasiveparticles, a pH adjusting agent that is used to adjust pH of the CMPcomposition to the optimized pH condition; a suitable chemical additiveto enhance/suppress the removal rate of polish designed film/stop layer;and the remaining being water.

The abrasive is present in an amount from 0.01 wt % to 20 wt %,preferably, from 0.05 wt % to 5 wt %, more preferably, from about 0.1 wt% to about 1 wt %.

Chemical additive includes, but is not limited to a compound having afunctional group selected from the group consisting of organiccarboxylic acids, amino acids, amidocarboxylic acids, N-acylamino acids,and their salts thereof; organic sulfonic acids and salts thereof;organic phosphonic acids and salts thereof; polymeric carboxylic acidsand salts thereof; polymeric sulfonic acids and salts thereof; polymericphosphonic acids and salts thereof; arylamines, aminoalcohols, aliphaticamines, heterocyclic amines, hydroxamic acids, substituted phenols,sulfonamides, thiols, polyols having hydroxyl groups, and combinationsthereof.

The amount of chemical additive ranges from about 0.1 ppm (or 0.000001wt %) to 0.5 wt % relative to the total weight of the barrier CMPcomposition. The preferred range is from about 200 ppm (or 0.02 wt %) to0.3 wt % and more preferred range is from about 500 ppm (or 0.05 wt %)to 0.15 wt %.

The pH-adjusting agent includes, but is not limited to, sodiumhydroxide, cesium hydroxide, potassium hydroxide, cesium hydroxide,ammonium hydroxide, quaternary organic ammonium hydroxide (e.g.tetramethylammonium hydroxide) and mixtures thereof.

The amount of pH-adjusting agent ranges from about 0.0001 wt % to about5 wt % relative to the total weight of the CMP composition. Thepreferred range is from about 0.0005 % to about 1 wt %, and morepreferred range is from about 0.0005 wt % to about 0.5 wt %

The pH of the CMP composition ranges from 2 to about 12; preferablyabout 3.5 to about 10; more preferably from about 4 to about 7.

For certain CMP applications such as Shallow Trench Isolation (STI) oroxide polish for 3D-NAND devices, it may be desirable to polish usingCMP formulations preferably in the range of 3 to 8 or most preferablybetween 4 to 7 in order to reduce dishing in the oxide line features aswell as to reduce loss of silicon nitride stopping layers. For certainapplications such as barrier metal polishing, the desirable pH range maybe 5 to 12, or more preferably between 8 to 11.

The CMP composition may comprise a surfactant or mixture of surfactants.Surfactant may be selected from groups comprising a). Non-ionicsurfactants; b). Anionic surfactants; c). Cationic surfactants; d).ampholytic surfactants; and mixtures thereof.

Non-ionic surfactants may be chosen from a range of chemical typesincluding but not limited to long chain alcohols, ethoxylated alcohols,ethoxylated acetylenic diol surfactants, polyethylene glycol alkylethers, proplylene glycol alkyl ethers, glucoside alkyl ethers,polyethylene glycol octylphenyl ethers, polyethylene glycol alkylpgenylethers, glycerol alkyl esters, polyoxyethylene glycol sorbiton alkylesters, sorbiton alkyl esters, cocamide monoethanol amine, cocamidediethanol amine dodecyl dimethylamine oxide, block copolymers ofpolyethylene glycol and polypropylene glycol, polyethoxylated tallowamines, fluorosurfactants. The molecular weight of surfactants may rangefrom several hundreds to over 1 million. The viscosities of thesematerials also possess a very broad distribution.

Anionic surfactants include, but are not limited to salts with suitablehydrophobic tails, such as alkyl carboxylate, alkyl polyacrylic salt,alkyl sulfate, alkyl phosphate, alkyl bicarboxylate, alkyl bisulfate,alkyl biphosphate, such as alkoxy carboxylate, alkoxy sulfate, alkoxyphosphate, alkoxy bicarboxylate, alkoxy bisulfate, alkoxy biphosphate,such as substituted aryl carboxylate, substituted aryl sulfate,substituted aryl phosphate, substituted aryl bicarboxylate, substitutedaryl bisulfate, substituted aryl biphosphate etc. The counter ions forthis type of surface wetting agents include, but are not limited topotassium, ammonium and other positive ions. The molecular weights ofthese anionic surface wetting agents range from several hundred toseveral hundred-thousands.

Cationic surface wetting agents possess the positive net charge on majorpart of molecular frame. Cationic surfactants are typically halides ofmolecules comprising hydrophobic chain and cationic charge centers suchas amines, quaternary ammonium, benzyalkonium and alkylpyridinium ions.

Yet, in another aspect, the surfactant can be an ampholytic surfacewetting agents possess both positive (cationic) and negative (anionic)charges on the main molecular chains and with their relative counterions. The cationic part is based on primary, secondary, or tertiaryamines or quaternary ammonium cations. The anionic part can be morevariable and include sulfonates, as in the sultaines CHAPS(3-[(3-Cholamidopropyl)dimethylammonio]-1-propanesulfonate) andcocamidopropyl hydroxysultaine. Betaines such as cocamidopropyl betainehave a carboxylate with the ammonium. Some of the ampholytic surfactantsmay have a phosphate anion with an amine or ammonium, such as thephospholipids phosphatidylserine, phosphatidylethanolamine,phosphatidylcholine, and sphingomyelins.

Examples of surfactants also include, but are not limited to, dodecylsulfate sodium salt, sodium lauryl sulfate, dodecyl sulfate ammoniumsalt, secondary alkane sulfonates, alcohol ethoxylate, acetylenicsurfactant, and any combination thereof. Examples of suitablecommercially available surfactants include TRITON™, Tergitol™, DOWFAX™family of surfactants manufactured by Dow Chemicals and varioussurfactants in SUIRFYNOL™, DYNOL™, Zetasperse™, Nonidet™, and Tomadol™surfactant families, manufactured by Air Products and Chemicals.Suitable surfactants of surfactants may also include polymers comprisingethylene oxide (EO) and propylene oxide (PO) groups. An example of EO-POpolymer is Tetronic™ 90R4 from BASF Chemicals.

Other surfactants that have functions of dispersing agents and/orwetting agents include, but are not limited to, polymeric compoundswhich may have anionic or cationic or nonionic or zwitterioniccharacteristics. Examples are polymers/copolymers containing functionalgroups such as acrylic acid, maleic acid, sulfonic acid, vinyl acid,ethylene oxide, etc.

The amount of surfactant ranges from about 0.0001 wt % to about 10 wt %relative to the total weight of the CMP composition. The preferred rangeis from about 0.001 wt % to about 1 wt %, and more preferred range isfrom about 0.005 wt % to about 0.1 wt %.

Formulations may also comprise water soluble polymers which may compriseanionic or cationic or non-ionic or combinations of groups. Thepolymer/copolymer has molecular weights greater than 1,000, rangingpreferably from 10,000 to 4,000,000; and more preferably from 50,000 to2,000,000. Polymers can be selected from a group of polymers including,but not limited to poly(acrylic acid), poly(meth-acrylic acid),poly(2-acrylamido-2-methyl-1-propanesulfonic acid, carboxymethylcellulose, methyl cellulose, hydroxypropyl methyl cellulose,poly-(1-vinylpyrroliddone-co-2-dimethylaminoethyl methacrylate). Polymerconcentration in the CMP formulation may be in the range of 0.001 wt %to 5 wt % or more preferably between 0.005 wt % to 2 wt % or mostpreferably between 0.01 wt % and 1 wt %.

Chelators, or chelating ligands may also be used to enhance affinity ofchelating ligands for metal cations especially in the applicationsinvolving polishing of metallic films. Chelating agents may also be usedto prevent build-up of metal ions on pads which causes pad staining andinstability in removal rates. Suitable chelators, or chelating ligandsinclude, but are not limited to, for example, benzenesulfonic acid,4-tolyl sulfonic acid, 2,4-diamino-benzosulfonic acid, and etc., andalso non-aromatic organic acids, such as itaconic acid, malic acid,malonic acid, tartaric acid, citric acid, oxalic acid, gluconic acid,lactic acid, mandelic acid, or salts thereof. The amount of chelators,or chelating ligands ranges from about 0.01 wt % to about 3.0 wt %relative to the total weight of the barrier CMP composition; preferablyfrom about 0.4 wt % to about 1.5 wt %.

The polishing composition may further comprise a corrosion inhibitor formetal polishing applications. Suitable corrosion inhibitors include, butare not limited to: benzotriazole (BTA) or BTA derivatives,3-amino-1,2,4-triazole, 3,5-diamine-1,2,4-triazole, other triazolederivatives, and combinations thereof.

The polishing composition includes an oxidizing agent, or oxidizer. Theoxidizing agent can be any suitable oxidizing agent. Suitable oxidizingagents include, but are not limited to, one or more peroxy-compounds,which comprise at least one peroxy group (O). Suitable peroxy-compoundsinclude, for example, peroxides, persulfates (e.g., monopersulfates anddipersulfates), percarbonates, and acids thereof, and salts thereof, andmixtures thereof. Other suitable oxidizing agents include, for example,oxidized halides (e.g., iodates, periodates, and acids thereof, andmixtures thereof, and the like), perboric acid, perborates,percarbonates, peroxyacids (e.g., peracetic acid, perbenzoic acid, saltsthereof, mixtures thereof, and the like), permanganates, ceriumcompounds, ferricyanides (e.g., potassium ferricyanide), mixturesthereof, and the like.

The CMP composition may comprise biological growth inhibitors orpreservatives to prevent bacterial and fungal growth during storage.

The biological growth inhibitors include, but are not limited to,tetramethylammonium chloride, tetraethylammonium chloride,tetrapropylammonium chloride, alkylbenzyldimethylammonium chloride, andalkylbenzyldimethylammonium hydroxide, wherein the alkyl chain rangesfrom 1 to about 20 carbon atoms, sodium chlorite, and sodiumhypochlorite.

Some of the commercially available preservatives include KATHON™ andNEOLENE™ product families from Dow Chemicals, and Preventol™ family fromLanxess. More are disclosed in U.S. Pat. No. 5,230,833 (Romberger etal.) and US Patent Application No. US 20020025762. The contents of whichare hereby incorporated by reference as if set forth in theirentireties.

Formulations may be made into concentrate and be diluted at the point ofuse. Alternatively, the formulations can be made into 2 or more multiplecomponents and mixed at the point of use.

WORKING EXAMPLES

Polishing Pad IC1010 pad, supplied by Dow Corporation was used for CMPprocess.

TEOS oxide films by Chemical Vapor Deposition (CVD) usingtetraethylorthosilicate as the precursor

HDP oxide films made by high density plasma (HDP) technique

SiN films—Silicon nitride films

Parameters:

Å: angstrom(s)—a unit of length

BP: back pressure, in psi units

CMP: chemical mechanical planarization=chemical mechanical polishing

CS: carrier speed

DF: Down force: pressure applied during CMP, units psi

min: minute(s)

ml: milliliter(s)

mV: millivolt(s)

psi: pounds per square inch

PS: platen rotational speed of polishing tool, in rpm (revolution(s) perminute)

SF: polishing composition flow, ml/min

Removal Rates and Removal Rate Selectivity

Removal Rate (RR)=(film thickness before polishing−film thickness afterpolishing)/polish time.

Removal Rate Selectivity of A over B=(RR of A)/(RR of B)

All percentages are weight percentages unless otherwise indicated.

Particle size distribution measurements were performed using the DiscCentrifuge Particle Size Analyzer (DC24000 UHR from CPS Instruments).Particle size distribution curves were generated based on assumptionthat particle size density of the composite particles is 3.64 gm/cm³calculated based on the composition of the particle.

Slurry formulations in subsequent examples use water as the remainder ofthe slurry formulation.

Example 1 Refining Composite Particles

20 wt % dispersion of ceria coated silica particles (CPOP-20) wasobtained from JGC C&C. The particle size of the core silica particle asmeasured by average diameter measurement by transmission electronmicroscopy (TEM) was approximately 100 nm. The ceria nanoparticle sizeas measured by average particle diameter measurement was approximately13 nm.

The particle dispersion was refined using two methods (1) Filtration;and (2) Fixed Angle Rotational Centrifuge.

Filtration was performed by passing the dispersion through 0.1 μmmembrane.

Fixed Angle Rotational Centrifuge (FARC) was operated at 1000 RPM speedfor one hour.

Under one condition (RE2003) in Fixed Angle Rotational Centrifuge, 1liter ceria dispersion was centrifuged and the top 30% fraction (300milliliters) was extracted for use.

Under another condition (RE2004) in Fixed Angle Rotational Centrifuge, 1liter ceria dispersion was centrifuged and the top 40% fraction (400milliliters) was extracted for use.

The particle size distributions were displayed in FIG. 2.

TABLE 1 Particle Size Distributions MPS (nm) D50 (nm) D75 (nm) D99 (nm)No Treatment 155 152.3 189.8 287.5 RE2003 102.5 104 118.3 165.3 RE2004105.7 109.1 128.6 181.1 Filtration 152.3 152 190.6 287.8

Table 1 summarizes the particle size distributions from original CPOP-20(No treatment), refined CPOP-20 after using Filtration, or FARC asmeasured by the Disc Centrifuge Particle Size Analyzer (DC24000 UHR fromCPS Instruments) (RE2003 and RE2004).

It's clear from FIG. 2 and table 1, that the RE2003 and RE2004treatments resulted in dramatic decrease in MPS, D50, D75 and D99. ForRE2003 and RE2004 treatments resulted, in a decrease in MPS from 155 nmto <106 nm.

The large sized aggregate particles were also drastically reduced asevident from decrease in D99 from 287.5 nm to less than 166 nm forRE2003 and less than 182 nm for RE2004.

Filtration had minimal impact on particle size distribution.

The particle size distribution was also used to calculate thedistribution of the particle clusters in terms of number of primaryparticles.

Table 2 summarized the distribution of particle clusters before andafter the FARC treatment.

It's clear as shown in Table 2 that FARC treatment reduced the size ofthe particle clusters dramatically. Most of the clusters found in theFARC samples had 4 or less (≦4) number of primary particles.

TABLE 2 Particle cluster distribution after the centrifuge treatmentParticles in Original RE2004 RE2003 cluster nm Wt % nm Wt % nm Wt % 1107 24% 102 59% 102 76% 2 130 19% 125 27% 125 22% 3 147 12% 140  7% >125 2% 4 159 11% 152  7% >4 >159 34% >155 100%  100%  100% 

Example 2 CMP Using Refined Composite Particles

The ceria dispersions described in Example 1, the original CPOP-20 (Notreatment), refined CPOP-20 after using Filtration, and FARC were usedin CMP formulations.

The CMP formulations were formulated with 0.75 wt % ceria coated silicaparticles, 0.077 wt % ammonium polyacrylate (molecular weight15000-18000).

pH of CMP formulations was adjusted to 5 using ammonium hydroxide.

TEOS wafers were polished on Reflexion™ LK polisher from AppliedMaterials™. IC1010™ pad from Dow Chemicals was used for polishing. Theplaten speed (PS) was 103 RPM and head speed (HS) was 93 RPM. Five zonepressure parameters (RR/Z1/Z2/Z3/Z4/Z5) were set at11.60/4.70/4.70/4.70/4.70/4.70 psi to provide a uniform downforce acrossthe wafer during polishing.

Removal rates and Within Wafer Removal Rate Non-Uniformity (WWNU (%))using the CMP formulations were summarized in Table 3.

TABLE 3 Effect of Particle Refinement on Removal rate and Within WaferRemoval Rate Non-Uniformity (WWNU (%)) TEOS RR (Å/min) WWNU (%) RE20034095 13 Filtered 2235 23 No treatment 2298 25

Table 3 showed that RE2003 sample obtained from FARC treatment which hadlower mean particle size and smaller size distribution offeredunexpectedly high removal rates and at the same time provided a veryflat removal rate distribution across the wafer surface.

Example 3 CMP Using Refined Composite Particles

CMP slurry formulations were made and tested in the same manner asdescribed in example 2. pH of these formulations was adjusted to 6.Additionally, TEOS wafers were analyzed on AIT-XP™ defect metrology toolfrom KLA-Tencor. Polishing procedure similar to example 2 was used inthese tests.

Table 4 summarized removal rate and defectivity data for theseformulations.

TABLE 4 Effect of Particle Refinement on Removal rate and Within WaferRemoval Rate Non-Uniformity Defects on TEOS RR (Å/min) NU (%) TEOS NoTreatment 1931 23.3 473 RE2004 2407 7.6 146 RE2003 2721 8.5 49

The results confirmed the beneficial effect of reduced particle size onremoval rate and non-uniformity. Furthermore, the results showed thebeneficial effect of reduced particle size on significant reduction indefects.

Example 4

Three groups A, B and C of ceria coated silica particles were obtainedby various particle size distribution refinement techniques. The ceriacoated silica particles had similar composite particle characteristicsin terms of core silica and ceria nano-particles covering the coreparticle.

Table 5 summarized the particle size distribution characteristics offour variants from those three groups of ceria coated silica particles.

TABLE 5 Particle Size Distribution Summary Mean Particle Size (MPS) (nm)D50 (nm) D75 (nm) D99 (nm) A 161 155 192 297 B 116 114 131 174 C 260 263358 481

FIG. 3 plotted the particle size distribution of those three group ofceria coated silica particles. Particle size distribution B was verynarrow with lower MPS, D50, D75 and D99 particle size. There were onlytwo peaks observable in the particle size distribution B, indicatingthat most of the particles are clusters involving 2 or less (≦2)composite particles. By contrast, particle size distribution A andparticle size distribution C showed 4 or more peaks indicating thatthere was substantial number of particles present with clusters 4 ormore composite particles.

CMP slurry formulations were made with 0.5 wt % of the ceria coatedsilica particles A, B and C. The formulations were pH adjusted usingammonium hydroxide.

Polishing was performed on 200 mm diameter TEOS wafers on Mirra™polisher from Applier Materials™. IC1010™ pad from Dow Chemicals wasused for polishing. Table speed was 87 RPM. Carrier speed was 93 RPM.Down-force was 3.7 psi.

Table 6 summarized the removal rate data of TEOS films.

TABLE 6 TEOS Removal rate data summary PSD used in CMP RR (Å/min) RR(Å/min) formulation pH 5 pH 6 A 5307 4806 B 7083 6653 C 3515 3583

The results summarized in table 6 suggest that particle sizedistribution B with lower D50, D75, D99, MPS and only two peaks inparticle size distribution provided unexpectedly high removal rates.

Example 5

CMP slurry formulations were made with 0.5 wt % of the ceria coatedsilica particles A, B and C as described in example 4. The formulationswere pH adjusted to 5 using ammonium hydroxide. Polishing was performedas per conditions described in example 4.

In some of the formulations, 0.1wt % ammonium polyacrylate (MW16000-18000) was added.

Table 7 summarizes the removal rate data.

The results showed that with the ammonium polyacrylate addition, siliconnitride removal rate was suppressed. The polymer acted as siliconnitride stopper, thus, optimal combination of high TEOS removal ratesand tunable TEOS/SiN removal rate selectivity can be achieved.

TABLE 7 Removal Rate Data Summary No Polymer Ammonium addition (RR(Å/min)) polyacrylate (RR (Å/min)) Selectivity Selectivity TEOS SiNTEOS/SiN TEOS SiN TEOS/SiN A 4680 286 16.4 1768 138 12.8 B 7083 1265 5.63566 157 22.7 C 3515 249 14.1 1417 140 10.1

The results summarized in table 7 also suggested that particle sizedistribution with lower D50, D75, D99 and MPS result in higher TEOS/SiNremoval rate selectivity.

The results also demonstrated that polishing formulations offered polishrates of silicon oxide at greater than 2000 Angstroms/min. while gavepolish rates of silicon nitride less than 160 Angstroms/min.

Example 6

CMP slurry formulation was made with 0.5 wt % of the ceria coated silicaparticles B and 0.1 wt % ammonium polyacrylate (MW 16000-18000) asdescribed in example 5. The formulation was pH adjusted to 6 usingammonium hydroxide. Polishing was performed as per conditions describedin example 5.

TABLE 8 Removal Rate (Å/min) Summary TEOS/SiN TEOS SiN Selectivity B3714 79 47

Table 8 summarized the removal rate data. The results showed that byincreasing pH to 6, selectivity of TEOS to nitride was further improvedto 47.

The present invention has demonstrated that composite particles withlower mean particle size and smaller size distribution could be obtainedthrough refining treatments. The refined composite particles were usedin CMP compositions to offer higher removal rate; very low within wafer(WWNU) for removal rate, low dishing and low defects.

The foregoing examples and description of the embodiments should betaken as illustrating, rather than as limiting the present invention asdefined by the claims. As will be readily appreciated, numerousvariations and combinations of the features set forth above can beutilized without departing from the present invention as set forth inthe claims. Such variations are intended to be included within the scopeof the following claims.

1. Composite particles comprise single ceria coated silica particles andaggregated ceria coated silica particles; wherein less than 1 wt % ofthe composite particles are aggregated ceria coated silica particlescomprising >5 single ceria coated silica particles.
 2. The compositeparticles of claim 1, wherein the composite particles have a featureselected from the group consisting of (a) 99 wt % of the compositeparticles have particle size less than 250 nm; (b) the compositeparticles have mean particle size less than 150 nm; and the meanparticle size is the weighted average of particle diameters; and (c)combination thereof.
 3. The composite particles of claim 1, wherein thecomposite particles have a feature selected from the group consisting of(a) less than 1 wt % of the composite particles are aggregated ceriacoated silica particles comprising >4 single ceria coated silicaparticles; (b) 99 wt % of the composite particles have particle sizeless than 200 nm; (c) the composite particles have mean particle sizeless than 125 nm or 110 nm; and (d) combinations thereof.
 4. Thecomposite particles of claim 1, wherein the composite particles have afeature selected from the group consisting of (a) less than 1 wt % ofthe composite particles are aggregated ceria coated silica particlescomprising >2 single ceria coated silica particles; (b) 99 wt % of thecomposite particles have particle size less than 200 nm; (c) thecomposite particles have mean particle size less than 110 nm; and (d)combinations thereof.
 5. The composite particles of claim 1, wherein theceria coated silica particles are amorphous silica particles havingsurfaces covered by singly crystalline ceria nanoparticles.
 6. Thecomposite particles of claim 1, wherein change of size distribution ofcomposite particles under a disintegrative force is less than 10%. 7.The composite particles of claim 1, wherein the change of sizedistribution of composite particles under a disintegrative force is lessthan 2%.
 8. A process of refining composite particles comprising singleand aggregated particles to reduce large aggregates, comprising at leastone step selected from the group consisting of (1) filtration; (2) bowlcentrifuge; (3) fixed angle rotational centrifuge; (4) gravitationalsettling; (5) optimization of calcination and milling processes; andcombinations thereof; wherein the single particles comprising coreparticles with surfaces covered by nanoparticles; the core particle isselected from the group consisting of silica, alumina, titania,zirconia, polymer particle, and combinations thereof; and thenanoparticle is selected from the compounds of a group consisting ofzirconium, titanium, iron, manganese, zinc, cerium, yttrium, calcium,magnesium, fluorine, lanthanum, strontium nanoparticle, and combinationsthereof.
 9. The process of claim 8, wherein less than 1 wt % of thecomposite particles after refining are aggregated ceria coated silicaparticles comprising >5 single ceria coated silica particles.
 10. Theprocess of claim 8, wherein the single and aggregated particles aresingle ceria coated silica particles and aggregated ceria coated silicaparticles; and the ceria coated silica particles are amorphous silicaceria particles having surfaces covered by singly crystalline ceriananoparticles.
 11. The process of claim 10, wherein refined compositeparticles have a feature selected from the group consisting of (a) lessthan 1 wt % of the composite particles after refining are aggregatedceria coated silica particles comprising >5 single ceria coated silicaparticles. (b) 99 wt % of the composite particles have particle sizeless than 250 nm; (c) the composite particles have mean particle sizeless than 150 nm; and the mean particle size is the weighted average ofparticle diameters; and (d) combination thereof.
 12. The process ofclaim 10, wherein refined composite particles have a feature selectedfrom the group consisting of (a) less than 1 wt % of the compositeparticles are aggregated ceria coated silica particles comprising >4single ceria coated silica particles; (b) 99 wt % of the compositeparticles have particle size less than 200 nm; (c) the compositeparticles have mean particle size less than 125 nm or 110 nm; and (d)combinations thereof.
 13. The process of claim 10, wherein change ofsize distribution of refined composite particles after refining under adisintegrative force is less than 10%.
 14. A chemical mechanicalplanarization (CMP) polishing composition, comprising 0.01 wt % to 20 wt% of composite particles comprise single ceria coated silica particlesand aggregated ceria coated silica particles; wherein less than 1 wt %of the composite particles are aggregated ceria coated silica particlescomprising >5 single ceria coated silica particles; water; pH of the CMPcomposition ranges from about 2 to about 12; and optionally 0.0001 wt %to about 5 wt % of a pH adjusting agent selected from the groupconsisting of sodium hydroxide, cesium hydroxide, potassium hydroxide,cesium hydroxide, ammonium hydroxide, quaternary organic ammoniumhydroxide, and combinations thereof; 0.000001 wt % to 0.5 wt % of achemical additive elected from the group consisting of a compound havinga functional group selected from the group consisting of organiccarboxylic acids, amino acids, amidocarboxylic acids, N-acylamino acids,and their salts thereof; organic sulfonic acids and salts thereof;organic phosphonic acids and salts thereof; polymeric carboxylic acidsand salts thereof; polymeric sulfonic acids and salts thereof; polymericphosphonic acids and salts thereof; arylamines, aminoalcohols, aliphaticamines, heterocyclic amines, hydroxamic acids, substituted phenols,sulfonamides, thiols, polyols having hydroxyl groups, and combinationsthereof; 0.0001 wt % to about 10 wt % of a surfactant selected from thegroup consisting of a). Non-ionic surface wetting agents; b). Anionicsurface wetting agents; c). Cationic surface wetting agents; d).ampholytic surface wetting agents; and combinations thereof; 0.001 wt %to 5 wt % of water soluble polymer selected from the group consisting ofanionic polymer, cationic polymer, non-ionic polymer, and combinationsthereof; 0.01 wt % to 3.0 wt % of chelators; corrosion inhibitor;oxidizer; and biological growth inhibitor.
 15. The chemical mechanicalplanarization (CMP) polishing composition of claim 14, wherein the CMPpolishing composition having pH from 3.5 to
 10. 16. The chemicalmechanical planarization (CMP) polishing composition of claim 14,wherein the composite particles have a feature selected from the groupconsisting of (a) 99 wt % of the composite particles have particle sizeless than 250 nm; (b) the composite particles have mean particle sizeless than 150 nm; and the mean particle size is the weighted average ofparticle diameters; and (c) combination thereof.
 17. The chemicalmechanical planarization (CMP) polishing composition of claim 14,wherein the composite particles have a feature selected from the groupconsisting of (a) less than 1 wt % of the composite particles areaggregated ceria coated silica particles comprising >4 single ceriacoated silica particles; (b) 99 wt % of the composite particles haveparticle size less than 200 nm; (c) the composite particles have meanparticle size less than 125 nm or 110 nm; and (d) combinations thereof.18. The chemical mechanical planarization (CMP) polishing composition ofclaim 14, wherein the CMP polishing composition comprising ceria coatedsilica particles, ammonium polyacrylate (molecular weight 15000-18000);the pH between 4 and 7; and less than 1 wt % of the composite particlesare aggregated ceria coated silica particles comprising >4 single ceriacoated silica particles.
 19. A polishing method for chemical mechanicalplanarization (CMP) of a semiconductor substrate comprising at least onesurface having at least one oxide layer, comprising the steps of: a)contacting the at least one oxide layer with a polishing pad; b)delivering a CMP polishing composition to the at least one surface, andc) polishing the at least one oxide layer with the CMP polishingcomposition; wherein the CMP polishing composition comprises 0.01 wt %to 20 wt % of composite particles comprise single ceria coated silicaparticles and aggregated ceria coated silica particles; wherein lessthan 1 wt % of the composite particles are aggregated ceria coatedsilica particles comprising >5 single ceria coated silica particles;water; pH of the CMP composition ranges from about 2 to about 12; andoptionally 0.0001 wt % to about 5 wt % of a pH adjusting agent selectedfrom the group consisting of sodium hydroxide, cesium hydroxide,potassium hydroxide, cesium hydroxide, ammonium hydroxide, quaternaryorganic ammonium hydroxide, and combinations thereof; 0.000001 wt % to0.5 wt % of a chemical additive elected from the group consisting of acompound having a functional group selected from the group consisting oforganic carboxylic acids, amino acids, amidocarboxylic acids,N-acylamino acids, and their salts thereof; organic sulfonic acids andsalts thereof; organic phosphonic acids and salts thereof; polymericcarboxylic acids and salts thereof; polymeric sulfonic acids and saltsthereof; polymeric phosphonic acids and salts thereof; arylamines,aminoalcohols, aliphatic amines, heterocyclic amines, hydroxamic acids,substituted phenols, sulfonamides, thiols, polyols having hydroxylgroups, and combinations thereof; 0.0001 wt % to about 10 wt % of asurfactant selected from the group consisting of a). Non-ionic surfacewetting agents; b). Anionic surface wetting agents; c). Cationic surfacewetting agents; d). ampholytic surface wetting agents; and mixturesthereof; 0.001 wt % to 5 wt % of water soluble polymer comprisinganionic polymer, cationic polymer, non-ionic polymer, and combinationsthereof; 0.01 wt % to 3.0 wt % of chelators; corrosion inhibitor;oxidizer; and biological growth inhibitor.
 20. The polishing method ofclaim 19, wherein the composite particles have a feature selected fromthe group consisting of (a) 99 wt % of the composite particles haveparticle size less than 250 nm; (b) the composite particles have meanparticle size less than 150 nm; and the mean particle size is theweighted average of particle diameters; and (c) combination thereof. 21.The polishing method of claim 19, wherein the composite particles have afeature selected from the group consisting of (a) less than 1 wt % ofthe composite particles are aggregated ceria coated silica particlescomprising >4 single ceria coated silica particles; (b) 99 wt % of thecomposite particles have particle size less than 200 nm; (c) thecomposite particles have mean particle size less than 125 nm or 110 nm;and (d) combinations thereof.
 22. The polishing method of claim 19,wherein the CMP polishing composition comprising ceria coated silicaparticles, ammonium polyacrylate (molecular weight 15000-18000); and thepH between 4 and 7; less than 1 wt % of the composite particles areaggregated ceria coated silica particles comprising>4 single ceriacoated silica particles; 99 wt % of the composite particles haveparticle size less than 200 nm; and the composite particles have meanparticle size less than 125 nm.
 23. The polishing method of claim 19,wherein the semiconductor substrate further comprising a nitride layerand removal selectivity of the at least one oxide layer over the nitridelayer is more than
 10. 24. The polishing method of claim 23, wherein theat least one oxide layer is TEOS and the semiconductor substrate furthercomprising a silicon nitride layer and removal selectivity of TEOS oversilicon nitride layer is more than 20.